Parâmetros biológicos, comportamentais e suscetibilidade de Hypothenemus hampei à diamidas

Abstract

The coffee borer (Hypothenemus hampei) is the main pest of coffee and the chemical method is the most used for its control, especially the group of diamides. That said, this study aimed to understand the biological and behavioral parameters as well as the susceptibility of H. hampei to diamides. The behavioral effects bioassays were performed at the Entomology Laboratory of the Federal University of Viçosa (UFV) - Viçosa (MG). Toxicity, survival, larval reproduction, behavioral response and respiration rate were assessed after exposure or non-exposure of adult insects to chloranthranilprole. The treatments of the LD50 and DL90 of chloranthraniliprole and control were used. Basic susceptibility line bioassays, population resistance monitoring and the risk of control failure were conducted at the Integrated Pest Management Laboratory at UFV - Rio Paranaíba (MG). The populations were collected in coffee-producing states from 2016 to 2018. In the artificial diet of H. hampei, the treatments of the LC50 (0.07 mg a.i. mL-1) and LC90 (0.57 mg a.i. mL-1) of cyantraniliprole, field dose (0.37 mg a.i. mL-1) and control were applied. Chloranthraniliprole was toxic to H. hampei (LD50 = 0.49 mg mL-1 and LD90 = 1.21 mg mL-1). The survival rate was 98% in adults not exposed to chlorantraniliprole, 52% in insects exposed to LD50 and 2% with LD90. At 20 days, LD90 affected the reproduction of H. hampei larvae, with the lowest number of live larvae (0.25), compared with LD50 (2.22 live larvae) and control (4.12 live larvae). Control adults moved the longest distance (3,871 cm) and spent less time at rest (185 s), while the LD50 (3,818 cm and 378 s) and LD90 (1,422 cm and 444 s) caused the opposite action. The respiration rate was regressive when exposed to the LD90 (0.33 μL of CO2 h-1 insect-1), LD50 (0.86 μL of CO2 h-1 insect-1) and control (1.59 μL of CO2 h-1 insect-1). Populations from Campo do Meio (MG), Linhares (ES) and Jaú (SP) were more susceptible (< 2-fold resistance) to cyantraniliprole than populations from Patrocínio (MG) and Londrina (PR) (17-fold). The frequency of cyantraniliprole resistant populations and the likelihood of control failure were low and not significant. The frequency of resistant insects and the control failure likelihood to cyantraniliprole were also low and not significant. The LD90 of chlorantraniliprole had negative effects in all behavioral tests. Populations remain susceptible to cyantraniliprole.